154 lines
6.3 KiB
Python
154 lines
6.3 KiB
Python
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# Protocol Buffers - Google's data interchange format
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# Copyright 2008 Google Inc. All rights reserved.
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# https://developers.google.com/protocol-buffers/
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# * Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above
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# copyright notice, this list of conditions and the following disclaimer
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# in the documentation and/or other materials provided with the
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# distribution.
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# * Neither the name of Google Inc. nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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"""Determine which implementation of the protobuf API is used in this process.
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"""
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import os
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import warnings
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import sys
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try:
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# pylint: disable=g-import-not-at-top
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from google.protobuf.internal import _api_implementation
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# The compile-time constants in the _api_implementation module can be used to
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# switch to a certain implementation of the Python API at build time.
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_api_version = _api_implementation.api_version
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_proto_extension_modules_exist_in_build = True
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except ImportError:
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_api_version = -1 # Unspecified by compiler flags.
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_proto_extension_modules_exist_in_build = False
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if _api_version == 1:
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raise ValueError('api_version=1 is no longer supported.')
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if _api_version < 0: # Still unspecified?
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try:
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# The presence of this module in a build allows the proto implementation to
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# be upgraded merely via build deps rather than a compiler flag or the
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# runtime environment variable.
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# pylint: disable=g-import-not-at-top
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from google.protobuf import _use_fast_cpp_protos
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# Work around a known issue in the classic bootstrap .par import hook.
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if not _use_fast_cpp_protos:
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raise ImportError('_use_fast_cpp_protos import succeeded but was None')
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del _use_fast_cpp_protos
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_api_version = 2
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except ImportError:
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try:
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# pylint: disable=g-import-not-at-top
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from google.protobuf.internal import use_pure_python
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del use_pure_python # Avoids a pylint error and namespace pollution.
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except ImportError:
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# TODO(b/74017912): It's unsafe to enable :use_fast_cpp_protos by default;
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# it can cause data loss if you have any Python-only extensions to any
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# message passed back and forth with C++ code.
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#
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# TODO(b/17427486): Once that bug is fixed, we want to make both Python 2
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# and Python 3 default to `_api_version = 2` (C++ implementation V2).
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pass
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_default_implementation_type = (
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'python' if _api_version <= 0 else 'cpp')
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# This environment variable can be used to switch to a certain implementation
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# of the Python API, overriding the compile-time constants in the
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# _api_implementation module. Right now only 'python' and 'cpp' are valid
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# values. Any other value will be ignored.
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_implementation_type = os.getenv('PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION',
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_default_implementation_type)
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if _implementation_type != 'python':
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_implementation_type = 'cpp'
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if 'PyPy' in sys.version and _implementation_type == 'cpp':
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warnings.warn('PyPy does not work yet with cpp protocol buffers. '
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'Falling back to the python implementation.')
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_implementation_type = 'python'
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# This environment variable can be used to switch between the two
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# 'cpp' implementations, overriding the compile-time constants in the
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# _api_implementation module. Right now only '2' is supported. Any other
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# value will cause an error to be raised.
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_implementation_version_str = os.getenv(
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'PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION', '2')
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if _implementation_version_str != '2':
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raise ValueError(
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'unsupported PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION: "' +
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_implementation_version_str + '" (supported versions: 2)'
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)
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_implementation_version = int(_implementation_version_str)
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# Detect if serialization should be deterministic by default
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try:
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# The presence of this module in a build allows the proto implementation to
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# be upgraded merely via build deps.
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#
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# NOTE: Merely importing this automatically enables deterministic proto
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# serialization for C++ code, but we still need to export it as a boolean so
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# that we can do the same for `_implementation_type == 'python'`.
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#
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# NOTE2: It is possible for C++ code to enable deterministic serialization by
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# default _without_ affecting Python code, if the C++ implementation is not in
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# use by this module. That is intended behavior, so we don't actually expose
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# this boolean outside of this module.
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#
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# pylint: disable=g-import-not-at-top,unused-import
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from google.protobuf import enable_deterministic_proto_serialization
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_python_deterministic_proto_serialization = True
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except ImportError:
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_python_deterministic_proto_serialization = False
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# Usage of this function is discouraged. Clients shouldn't care which
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# implementation of the API is in use. Note that there is no guarantee
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# that differences between APIs will be maintained.
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# Please don't use this function if possible.
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def Type():
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return _implementation_type
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def _SetType(implementation_type):
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"""Never use! Only for protobuf benchmark."""
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global _implementation_type
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_implementation_type = implementation_type
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# See comment on 'Type' above.
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def Version():
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return _implementation_version
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# For internal use only
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def IsPythonDefaultSerializationDeterministic():
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return _python_deterministic_proto_serialization
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